Volatile or essential oils are widely used in oral care products. Essential oils are aromatic compounds that are either derived from plant sources or are synthesized. Some essential oils show long-lasting germicidal effectiveness against the most common pathogens in the mouth. These pathogens are frequently associated with oral malodor, plaque, and gingivitis. Thymol is an essential oil that is well-known and widely used as an antimicrobial in oral care products. Other essential oils include menthol, methyl salicylate, eucalyptol, anethol and eugenol.
Essential oils have been used for years in antiseptic and antiplaque mouthwash solutions. For example, LISTERINE.RTM. antiseptic mouthwash has been marketed since 1881, and contains the essential oils thymol, menthol, eucalyptol, and methyl salicylate. More recently, essential oils have been included in formulations of toothpaste. U.S. Pat. No. 1,526,940 to Staegemann teaches a toothpaste with the germicide ammonium ichthyol sulphonate with high amounts of thymol, menthol, eucalyptol, methyl salicylate, and peppermint oil as flavorants and taste-masking ingredients.
U.S. Pat. No. 3,164,524 to Fand et al. teaches an oral antiseptic comprising 2, 2'-thiobis-(4,6-dichlorophenol), boric acid, methyl salicylate, thymol, menthol and eucalyptol.
U.S. Pat. No. 5,094,843 to Mazzanobile et al. teaches an anti-plaque, anti-gingivitis toothpaste with a flourine source, and a specific range of thymol, menthol, methyl salicylate and eucalyptol.
European Patent Application 04974776 to Colgate-Palmolive Co. teaches an antiplaque oral composition, including a toothpaste, with triclosan. The antiplaque activity of the triclosan is increased by essential oils such as eucalyptol, thymol, methyl salicylate, and menthol.
U.S. Patents Nos. 4,545,979 and 4,550,018 to Ambike et al. teach a dental hygiene composition in an acidic pH range of from 3.0 to 5.0, pH buffers, fluoride, thymol, eucalyptol, methyl salicylate, peppermint and spearmint oil flavors, and 0.1 to 2.0 percent by weight of one or more highly pure alkali metal salts of dodecyl sulphate having less than 5% non-dodecyl alkyl sulphate salts.
Canadian Pat. No. 834131 to Tisserand teaches a dentifrice preparation that has an acidic pH of about 3.8 to 5.8, optimally a pH of 4.0 to 5.5, and most preferably a pH of 4.0 to 4.8; fluoride; and menthol, methyl salicylate and thyme oil flavor oils that are substantially free of hydrocarbon terpenes. According to Tisserand when essential oils which are not free of terpenes are employed in a fluoride dentifrice which has a pH in the range of about 3.8 to 5.8 the flavor develops a pronounced rancid and sour taste in a period of less than 3 months.
Warner-Lambert has marketed Euthymol.RTM. Toothpaste that was formulated with thymol, eucalyptol, methyl salicylate and menthol at a pH above 7.0. This toothpaste was not formulated with fluoride. Warner-Lambert has also marketed Listerine.RTM. toothpaste in the United States and Canada that did not contain thyrmol or eucalyptol and was formulated at a pH above 6.0. This toothpaste did not contain fluoride.
Mazzanobile et. al, U.S. Pat. No. 4,830,221 discloses a dentifrice formulated at a pH of between about 3.5 and about 9.5. Eucalyptus, thyme, menthol, and methyl salicylate are among the flavoring oils that are disclosed. There is no mention of the use of flavor oils in antiseptically effective amounts.
While the prior art discloses toothpaste and other dentifrice compositions with antiseptic essential oils, there is no teaching or suggestion regarding the optimum pH at which these compositions containing essential oils should be formulated. It has surprisingly been found that the antiseptic activity of dentifrice compositions with essential oils is enhanced when the pH of the composition is between about 3.0 and about 5.5.
It is therefore an object of the present invention to provide an antiseptic dentifrice composition that helps reduce oral malodor, formulated with essential oils at an acid pH of between about 3.0 and about 5.5 to enhance the antiseptic activity of the composition.
Another object of this present invention is to provide an antiseptic and anticaries dentifrice composition with essential oils and a fluoride-releasing compound formulated at an acid pH of between about 3.0 and 5.5 to enhance the antiseptic activity of the composition while maintaining effective anticaries activity.